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diff --git a/examples/snavely_reprojection_error.h b/examples/snavely_reprojection_error.h new file mode 100644 index 0000000..0704217 --- /dev/null +++ b/examples/snavely_reprojection_error.h @@ -0,0 +1,156 @@ +// Ceres Solver - A fast non-linear least squares minimizer +// Copyright 2010, 2011, 2012 Google Inc. All rights reserved. +// http://code.google.com/p/ceres-solver/ +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are met: +// +// * Redistributions of source code must retain the above copyright notice, +// this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above copyright notice, +// this list of conditions and the following disclaimer in the documentation +// and/or other materials provided with the distribution. +// * Neither the name of Google Inc. nor the names of its contributors may be +// used to endorse or promote products derived from this software without +// specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" +// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE +// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR +// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF +// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN +// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) +// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +// POSSIBILITY OF SUCH DAMAGE. +// +// Author: sameeragarwal@google.com (Sameer Agarwal) +// +// Templated struct implementing the camera model and residual +// computation for bundle adjustment used by Noah Snavely's Bundler +// SfM system. This is also the camera model/residual for the bundle +// adjustment problems in the BAL dataset. It is templated so that we +// can use Ceres's automatic differentiation to compute analytic +// jacobians. +// +// For details see: http://phototour.cs.washington.edu/bundler/ +// and http://grail.cs.washington.edu/projects/bal/ + +#ifndef CERES_EXAMPLES_SNAVELY_REPROJECTION_ERROR_H_ +#define CERES_EXAMPLES_SNAVELY_REPROJECTION_ERROR_H_ + +#include "ceres/rotation.h" + +namespace ceres { +namespace examples { + +// Templated pinhole camera model for used with Ceres. The camera is +// parameterized using 9 parameters: 3 for rotation, 3 for translation, 1 for +// focal length and 2 for radial distortion. The principal point is not modeled +// (i.e. it is assumed be located at the image center). +struct SnavelyReprojectionError { + SnavelyReprojectionError(double observed_x, double observed_y) + : observed_x(observed_x), observed_y(observed_y) {} + + template <typename T> + bool operator()(const T* const camera, + const T* const point, + T* residuals) const { + // camera[0,1,2] are the angle-axis rotation. + T p[3]; + ceres::AngleAxisRotatePoint(camera, point, p); + + // camera[3,4,5] are the translation. + p[0] += camera[3]; + p[1] += camera[4]; + p[2] += camera[5]; + + // Compute the center of distortion. The sign change comes from + // the camera model that Noah Snavely's Bundler assumes, whereby + // the camera coordinate system has a negative z axis. + const T& focal = camera[6]; + T xp = - p[0] / p[2]; + T yp = - p[1] / p[2]; + + // Apply second and fourth order radial distortion. + const T& l1 = camera[7]; + const T& l2 = camera[8]; + T r2 = xp*xp + yp*yp; + T distortion = T(1.0) + r2 * (l1 + l2 * r2); + + // Compute final projected point position. + T predicted_x = focal * distortion * xp; + T predicted_y = focal * distortion * yp; + + // The error is the difference between the predicted and observed position. + residuals[0] = predicted_x - T(observed_x); + residuals[1] = predicted_y - T(observed_y); + + return true; + } + + double observed_x; + double observed_y; +}; + +// Templated pinhole camera model for used with Ceres. The camera is +// parameterized using 10 parameters. 4 for rotation, 3 for +// translation, 1 for focal length and 2 for radial distortion. The +// principal point is not modeled (i.e. it is assumed be located at +// the image center). +struct SnavelyReprojectionErrorWithQuaternions { + // (u, v): the position of the observation with respect to the image + // center point. + SnavelyReprojectionErrorWithQuaternions(double observed_x, double observed_y) + : observed_x(observed_x), observed_y(observed_y) {} + + template <typename T> + bool operator()(const T* const camera_rotation, + const T* const camera_translation_and_intrinsics, + const T* const point, + T* residuals) const { + const T& focal = camera_translation_and_intrinsics[3]; + const T& l1 = camera_translation_and_intrinsics[4]; + const T& l2 = camera_translation_and_intrinsics[5]; + + // Use a quaternion rotation that doesn't assume the quaternion is + // normalized, since one of the ways to run the bundler is to let Ceres + // optimize all 4 quaternion parameters unconstrained. + T p[3]; + QuaternionRotatePoint(camera_rotation, point, p); + + p[0] += camera_translation_and_intrinsics[0]; + p[1] += camera_translation_and_intrinsics[1]; + p[2] += camera_translation_and_intrinsics[2]; + + // Compute the center of distortion. The sign change comes from + // the camera model that Noah Snavely's Bundler assumes, whereby + // the camera coordinate system has a negative z axis. + T xp = - p[0] / p[2]; + T yp = - p[1] / p[2]; + + // Apply second and fourth order radial distortion. + T r2 = xp*xp + yp*yp; + T distortion = T(1.0) + r2 * (l1 + l2 * r2); + + // Compute final projected point position. + T predicted_x = focal * distortion * xp; + T predicted_y = focal * distortion * yp; + + // The error is the difference between the predicted and observed position. + residuals[0] = predicted_x - T(observed_x); + residuals[1] = predicted_y - T(observed_y); + + return true; + } + + double observed_x; + double observed_y; +}; + +} // namespace examples +} // namespace ceres + +#endif // CERES_EXAMPLES_SNAVELY_REPROJECTION_ERROR_H_ |